To make the lazy FPSIMD context switch trap code easier to hack on,
this patch converts it to C.
This is not amazingly efficient, but the trap should typically only
be taken once per host context switch.
Signed-off-by: Dave Martin <dave.mar...@arm.com>
Reviewed-by: Marc Zyngier <marc.zyng...@arm.com>
---
arch/arm64/kvm/hyp/entry.S | 57 +++++++++++++++++----------------------------
arch/arm64/kvm/hyp/switch.c | 24 +++++++++++++++++++
2 files changed, 46 insertions(+), 35 deletions(-)
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index e41a161..40f349b 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -172,40 +172,27 @@ ENTRY(__fpsimd_guest_restore)
// x1: vcpu
// x2-x29,lr: vcpu regs
// vcpu x0-x1 on the stack
- stp x2, x3, [sp, #-16]!
- stp x4, lr, [sp, #-16]!
-
-alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
- mrs x2, cptr_el2
- bic x2, x2, #CPTR_EL2_TFP
- msr cptr_el2, x2
-alternative_else
- mrs x2, cpacr_el1
- orr x2, x2, #CPACR_EL1_FPEN
- msr cpacr_el1, x2
-alternative_endif
- isb
-
- mov x3, x1
-
- ldr x0, [x3, #VCPU_HOST_CONTEXT]
- kern_hyp_va x0
- add x0, x0, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
- bl __fpsimd_save_state
-
- add x2, x3, #VCPU_CONTEXT
- add x0, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
- bl __fpsimd_restore_state
-
- // Skip restoring fpexc32 for AArch64 guests
- mrs x1, hcr_el2
- tbnz x1, #HCR_RW_SHIFT, 1f
- ldr x4, [x3, #VCPU_FPEXC32_EL2]
- msr fpexc32_el2, x4
-1:
- ldp x4, lr, [sp], #16
- ldp x2, x3, [sp], #16
- ldp x0, x1, [sp], #16
-
+ stp x2, x3, [sp, #-144]!
+ stp x4, x5, [sp, #16]
+ stp x6, x7, [sp, #32]
+ stp x8, x9, [sp, #48]
+ stp x10, x11, [sp, #64]
+ stp x12, x13, [sp, #80]
+ stp x14, x15, [sp, #96]
+ stp x16, x17, [sp, #112]
+ stp x18, lr, [sp, #128]
+
+ bl __hyp_switch_fpsimd
+
+ ldp x4, x5, [sp, #16]
+ ldp x6, x7, [sp, #32]
+ ldp x8, x9, [sp, #48]
+ ldp x10, x11, [sp, #64]
+ ldp x12, x13, [sp, #80]
+ ldp x14, x15, [sp, #96]
+ ldp x16, x17, [sp, #112]
+ ldp x18, lr, [sp, #128]
+ ldp x0, x1, [sp, #144]
+ ldp x2, x3, [sp], #160
eret
ENDPROC(__fpsimd_guest_restore)
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index d964523..c0796c4 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -318,6 +318,30 @@ static bool __hyp_text __skip_instr(struct kvm_vcpu *vcpu)
}
}
+void __hyp_text __hyp_switch_fpsimd(u64 esr __always_unused,
+ struct kvm_vcpu *vcpu)
+{
+ kvm_cpu_context_t *host_ctxt;
+
+ if (has_vhe())
+ write_sysreg(read_sysreg(cpacr_el1) | CPACR_EL1_FPEN,
+ cpacr_el1);
+ else
+ write_sysreg(read_sysreg(cptr_el2) & ~(u64)CPTR_EL2_TFP,
+ cptr_el2);
+
+ isb();
+
+ host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
+ __fpsimd_save_state(&host_ctxt->gp_regs.fp_regs);
+ __fpsimd_restore_state(&vcpu->arch.ctxt.gp_regs.fp_regs);
+
+ /* Skip restoring fpexc32 for AArch64 guests */
+ if (!(read_sysreg(hcr_el2) & HCR_RW))
+ write_sysreg(vcpu->arch.ctxt.sys_regs[FPEXC32_EL2],
+ fpexc32_el2);
+}
+
/*
* Return true when we were able to fixup the guest exit and should return to
* the guest, false when we should restore the host state and return to the
--
2.1.4
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